During the measurement of a spinning object's surface, the distribution of sampling points to be measured is usually tighter when associated measurement positions are closer to a spin axis; otherwise, the distribution of sampling points to be measured is usually looser when associated measurement positions are farther from the spin axis. This causes the uneven distribution of sampling points to be measured on the object's surface. That is, such a conventional way to measure a spinning object may not evenly sample an object's surface for the acquirement of the accurate status of the object's surface or for the analysis of the object's surface.
For example, most of modern technologies use the chemical mechanical polishing (CMP) technology to smooth semiconductor wafers' surfaces. The polishing apparatus based on this technology usually makes a spinning polishing pad and a semiconductor wafer oppositely move in order to smooth the semiconductor wafer's surface. Therefore, in the chemical-mechanical polishing technology the surface roughness of the polishing pad greatly affects the smooth quality of semiconductor wafers. If a technology capable of evenly sampling the surface of a spinning polishing pad is promoted, the surface status of the polishing pad may be handled more accurately, whereby the chemical-mechanical polishing technology may have a higher efficiency and the cost of polishing semiconductor wafers may be controlled more efficiently.